From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 06/41] perf tools: Preserve eBPF maps when loading kcore Date: Wed, 29 May 2019 10:35:30 -0300 Message-ID: <20190529133605.21118-7-acme@kernel.org> References: <20190529133605.21118-1-acme@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190529133605.21118-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar , Thomas Gleixner Cc: Jiri Olsa , Namhyung Kim , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Adrian Hunter , Song Liu , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Peter Zijlstra , Stanislav Fomichev List-Id: linux-perf-users.vger.kernel.org From: Jiri Olsa We need to preserve eBPF maps even if they are covered by kcore, because we need to access eBPF dso for source data. Add the map_groups__merge_in function to do that. It merges a map into map_groups by splitting the new map within the existing map regions. Suggested-by: Adrian Hunter Signed-off-by: Jiri Olsa Acked-by: Song Liu Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stanislav Fomichev Link: http://lkml.kernel.org/r/20190508132010.14512-9-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 97 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 93 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 5cbad55cd99d..29780fcd049c 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1166,6 +1166,85 @@ static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data) return 0; } +/* + * Merges map into map_groups by splitting the new map + * within the existing map regions. + */ +static int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map) +{ + struct map *old_map; + LIST_HEAD(merged); + + for (old_map = map_groups__first(kmaps); old_map; + old_map = map_groups__next(old_map)) { + + /* no overload with this one */ + if (new_map->end < old_map->start || + new_map->start >= old_map->end) + continue; + + if (new_map->start < old_map->start) { + /* + * |new...... + * |old.... + */ + if (new_map->end < old_map->end) { + /* + * |new......| -> |new..| + * |old....| -> |old....| + */ + new_map->end = old_map->start; + } else { + /* + * |new.............| -> |new..| |new..| + * |old....| -> |old....| + */ + struct map *m = map__clone(new_map); + + if (!m) + return -ENOMEM; + + m->end = old_map->start; + list_add_tail(&m->node, &merged); + new_map->start = old_map->end; + } + } else { + /* + * |new...... + * |old.... + */ + if (new_map->end < old_map->end) { + /* + * |new..| -> x + * |old.........| -> |old.........| + */ + map__put(new_map); + new_map = NULL; + break; + } else { + /* + * |new......| -> |new...| + * |old....| -> |old....| + */ + new_map->start = old_map->end; + } + } + } + + while (!list_empty(&merged)) { + old_map = list_entry(merged.next, struct map, node); + list_del_init(&old_map->node); + map_groups__insert(kmaps, old_map); + map__put(old_map); + } + + if (new_map) { + map_groups__insert(kmaps, new_map); + map__put(new_map); + } + return 0; +} + static int dso__load_kcore(struct dso *dso, struct map *map, const char *kallsyms_filename) { @@ -1222,7 +1301,12 @@ static int dso__load_kcore(struct dso *dso, struct map *map, while (old_map) { struct map *next = map_groups__next(old_map); - if (old_map != map) + /* + * We need to preserve eBPF maps even if they are + * covered by kcore, because we need to access + * eBPF dso for source data. + */ + if (old_map != map && !__map__is_bpf_prog(old_map)) map_groups__remove(kmaps, old_map); old_map = next; } @@ -1256,11 +1340,16 @@ static int dso__load_kcore(struct dso *dso, struct map *map, map_groups__remove(kmaps, map); map_groups__insert(kmaps, map); map__put(map); + map__put(new_map); } else { - map_groups__insert(kmaps, new_map); + /* + * Merge kcore map into existing maps, + * and ensure that current maps (eBPF) + * stay intact. + */ + if (map_groups__merge_in(kmaps, new_map)) + goto out_err; } - - map__put(new_map); } if (machine__is(machine, "x86_64")) { -- 2.20.1